Here's a link to the manual for your Aprilaire model 560 humidifier you can download and print for free.
According to Aprilaire, it is normal for there to be excess water going into the drain pan. However, the drain pan should have a drain line connected to it so the contaminents from the humidifier can be flushed down a drain and away from the unit. (see page 2 Principle of Operation).
They further state that the water valve should only be either fully on or fully shut off and do not attempt to regulate water flow with the inlet supply valve.
I would give the unit a good cleaning of the pan, locate the drain connection and attach a drain line to your unit as is required for proper operation and function/
Answers & Comments
Here's a link to the manual for your Aprilaire model 560 humidifier you can download and print for free.
According to Aprilaire, it is normal for there to be excess water going into the drain pan. However, the drain pan should have a drain line connected to it so the contaminents from the humidifier can be flushed down a drain and away from the unit. (see page 2 Principle of Operation).
They further state that the water valve should only be either fully on or fully shut off and do not attempt to regulate water flow with the inlet supply valve.
http://www.aprilaire.com/themes/aa/en/manuals/Humidifiers_Owners_Manual.pdf
I would give the unit a good cleaning of the pan, locate the drain connection and attach a drain line to your unit as is required for proper operation and function/
Hope you find this Very Helpful - Best regards!